1. Field of the Invention:
This invention relates to the mounting of a substantially planar diaphragm defining a sound transducer, and more particularly it refers to the mounting preferably used for small surface diaphragms which may be used amongst others as loudspeakers for motor cars.
However, it should be clearly understood that the invention is likewise applicable to other fields, such as upon manufacturing a substantially planar diaphragm of a cellular material having sealed cells, for instance made of polystyrene, such diaphragm can work in combination with a hermetically sealed electromagnetic assembly, underwater, and it may there operate both as a microphone as well as a loudspeaker, so that several divers may communicate underwater or instructions may be transmitted to dolphins.
2. Description of the Prior Art:
Flat or planar loudspeakers with an excellent output are already known, when the size of the diaphragm is rather substantial of the type of 70 cm x 50 cm, because it is then possible to surround the zone destinated to vibrate in order to generate the sound, by a substantial marginal zone made of the same material as the vibrating zone and only such marginal zone is mounted by its peripheral portion on a stationary frame. Thus, the vibrating zone of the diaphragm is suitably guided without there existing any danger of undesirable deviations, which could harm the driver unit of the electro-magnetic assembly. More particularly, there is no substantial danger that the coil of such electro-magnetic assembly could be deviated within its gap to even reach the point where the coil enters in frictional contact with the magnet. This type of planar loudspeaker has been disclosed in my previous U.S. Pat. Nos. 3,596,733, 3,801,943 and 3,779,336.
Loudspeakers of the common frusto-conical diaphragm type, when used in motor-cars, are usually located in a horizontal position so that the opening or mouth of the frusto-conical diaphragm defines a good dust-collector of the dust and other particles floating in the air and have a tendency to fall into the diaphragm entering the gap of the electro-magnetic driver and thereby, sooner or later, establishing a frictional connection which represents the end of a good sound transmission.